Minimizing drive test logged data reporting

ABSTRACT

This disclosure pertains to a method in a network node, a method in user equipment, a network node and user equipment in a wireless communications network. More particularly, there is provided methods and platforms for network based control of report messages comprising logged measurements in a wireless communications network. In accordance with some example embodiments, a UE ( 30 ) that has stored logged data i.e. logged measurements that are bigger than a single transmission packet, i.e. report message, segments the logged measurements and sends only a portion of the logged measurements that fits into a single report message. The UE ( 30 ) also indicates to a network node ( 28 ) that additional logged measurements exist at the UE buffer ( 44 ).

RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.15/049,271 filed on Feb. 22, 2016 entitled “Minimizing Drive Test LoggedData Reporting, which is a continuation of U.S. application Ser. No.14/311,606 filed on Jun. 23, 2014 entitled “Minimizing Drive Test LoggedData Reporting”, which is a continuation of U.S. application Ser. No.13/001,687 filed Oct. 14, 2011 entitled “Minimizing Drive Test LoggedData Reporting,” which is a U.S. National Stage Filing under 35 U.S.C.§371 of International Patent Application Serial No. PCT/SE2010/051355,filed Dec. 9, 2010 and entitled “Network Based Control of ReportMessages in A Wireless Communications Network,” which claims thepriority benefit of U.S. Provisional Application Ser. No. 61/389,581,filed Oct. 4, 2010 and entitled “Minimizing Drive Test Logged DataReporting,” all of which are incorporated herein by reference in theirentirety.

TECHNICAL FIELD

This disclosure pertains to a method in a network node, a method in userequipment, a network node and user equipment in a wirelesscommunications network. More particularly, there is provided mechanismsfor network based control of report messages comprising loggedmeasurements in a wireless communications network.

BACKGROUND

In a typical cellular radio system, wireless terminals, also known asmobile stations and/or User Equipments units (UEs), communicate via aRadio Access Network (RAN) to one or more core networks. The wirelessterminals, hereinafter called UEs which is the same as User Equipments,can also be mobile telephones, i.e. “cellular” telephones, and laptopswith wireless capability e.g., mobile termination, and thus are, forexample, portable, pocket, hand-held, computer-included, or car-mountedmobile devices which communicate voice and/or data via the RAN.

The RAN normally covers a geographical area which is divided into cellareas, also denoted cells, with each cell area being served by a basestation e.g., a Radio Base Station (RBS), which in some networks is alsocalled “NodeB” or “B node”. A cell is a geographical area where radiocoverage is provided by base station equipment at a base station site.Each cell is identified by an identity within the local radio area,which is broadcast in the cell. The base station communicates over theair interface operating on radio frequencies with the UEs within rangeof the base stations.

In some versions, particularly earlier versions of the RAN, several basestations are typically connected, e.g., by landlines or microwave, to aRadio Network Controller (RNC). The RNC, also sometimes termed a BaseStation Controller (BSC), supervises and coordinates various activitiesof the plural base stations connected thereto. The radio networkcontrollers are typically connected to one or more core networks.

The Universal Mobile Telecommunications System (UMTS) is a thirdgeneration mobile communication system, which evolved from the GlobalSystem for Mobile Communications (GSM), and is intended to provideimproved mobile communication services based on Wideband Code DivisionMultiple Access (WCDMA) access technology. UTRAN is essentially a radioaccess network using wideband code division multiple access for userequipment units (UEs). The Third Generation Partnership Project (3GPP)has undertaken to evolve further the UTRAN and GSM based radio accessnetwork technologies.

Long Term Evolution (LTE) is a variant of a 3GPP radio access technologywherein the radio base station nodes are connected directly to a corenetwork rather than to RNCs. In general, in LTE the functions of the RNCnode are performed by the RBSs. As such, the RAN of an LTE system has anessentially “flat” architecture comprising RBSs without reporting toRNCs. In LTE networks the base station(s) is/are called eNodeB(s) oreNB(s).

3GPP is in the process of defining solutions for Minimizing Drive Tests(MDT). The intention of the Minimizing Drive Tests (MDT) work isdocumented in 3GPP TR 36.805 V9.0.0 (2009-12), 3rd GenerationPartnership Project; Technical Specification Group Radio Access Network;Study on Minimization of drive-tests in Next Generation Networks(Release 9).

Stage 2 of Minimizing Drive Tests (MDT) is currently being developed inTS 37.320, i.e., 3GPP TS 37.320, “Radio measurement collection forMinimization of Drive Tests (MDT); Overall description; Stage 2”. MDTStage 2 includes a UE measurement logging function and immediatereporting function. The 3GPP TS 37.320 document essentially focuses onthe UE measurement logging function.

An important use case for MDT is coverage optimization. For this purposefollowing UE measurements, or similar functionalities, are consideredfor UE-internal logging: Periodic, e.g. one every 5 s, downlink pilotsignal strength measurements; a serving cell becomes worse thanthreshold; transmit power headroom becomes less than threshold; PagingChannel Failure i.e. Paging Control CHannel (PCCH) decode error; andBroadcast Channel failure.

The network can request the UE to perform logging of measurements. TheUE executes measurements and logs these measurements internally in asequential manner, containing, e.g., some hour of logged measurementinformation.

As described in FIG. 1, the UE indicates to the network if it hasavailable log i.e. available logged measurements. The network node i.e.eNB/RNC determines if it should request the logged measurements or not.If it decides to do so then a request is sent to the UE to deliver thelog in a report message. From the eNB/RNC, the reported loggedmeasurements may further be sent to an OAM server or similar.

The current 3GPP assumptions on this log (i.e. logged measurements)feature are, e.g., as follows: the UE is required to maintain only onelog at a time; one log only contains measurement information collectedin one Radio Access Technology (RAT); a log can only be reported andindicated when the UE is in connected state; If UE is requested to startlogging, e.g., by configuration, a possibly old log and configurationstored in UE is erased.

What the logged measurement report message in signal number 4 in FIG. 1should look like has not yet been decided, as of the filing of thisapplication. Some proposals for management of measurement report havebeen proffered.

As one example proposal for management of measurement reports, it hasbeen suggested that a log i.e. logged measurements, are to be sent in asingle packet, and keeping that single packet within the size limits ofa Packet Data Convergence Protocol (PDCP) Protocol Data Unit (PDU).Keeping the single packet within the size limits of a PDCP PDU makes itpossible to use a Radio Resource Control RRC message for reportingwithout being segmented into several smaller packets before being sentto the receiving node i.e., the eNB or NB/RNC in LTE or UMTS,respectively. One option of this proposal would be limiting the maximumsize of a log in a UE to one RRC message that fits into one PDCP payloadpacket.

As another example proposal for management of measurement reports, ithas been suggested to send a log i.e. a logged measurement that islarger than a RRC message with several RRC messages.

However, there are disadvantages to both example proposals mentionedabove. For example, limiting the log size could prevent logging tocomplete for the whole configured run time i.e. logging duration, whichcan be several hours. The log could fill the limited log buffer in theUE before any measurement report has been possible to send to thenetwork node. Before the configured logging duration time has ended, theUE would stop the logging so that to only allow the log size to be asingle packet e.g. single RRC packet, and relevant measurements reportsmay not thereafter be logged. Also in the current MDT configuration astart time for the logging is not configurable. This means that for aprolonged logging campaign a long period between logging instances maybe needed in the MDT configuration, alternatively new MDT configurationneeds to be provided from the OAM periodically to be conveyed to MDTcapable UEs.

For the other proposal, sending too many RRC packets in a row could, inpoor radio environments or when handover would occur, create problemswith the radio connections and could also create unnecessary radio linkfailures that will make the users suffer and logged data be lost.

SUMMARY

The technology disclosed herein concerns network based control of reportmessages comprising logged measurements in a wireless communicationsnetwork, which overcomes at least some of the above mentioneddisadvantages and which allows multiple partial report messages to besent.

In accordance with some example embodiments, a UE that has stored loggeddata i.e. logged measurements that are bigger than a single transmissionpacket, i.e. report message, segments the data and sends only a portionof the data that fits into a single report message, and also indicatesthat more logged measurements exists at the UE.

In a first example of embodiment, there is disclosed a method in anetwork node for network based control of report messages in a wirelesscommunications network. The network node being configured to serve auser equipment, UE, and to receive report messages from the userequipment. The method comprises sending a request to the UE to starttransmitting logged measurements in a report message. The network nodethen receives the report message comprising the logged measurements fromthe UE, and determines if the received report message comprises anindicator of additional logged measurements not yet transmitted, and ifso, decides if the additional logged measurements need to be requested.

In a second example of an embodiment there is disclosed a network nodefor network based control of report messages in a wirelesscommunications network. The network node being configured to serve auser equipment, UE, and to receive report messages from the userequipment. The network node comprises a network node communicationsinterface and a network node processor circuit. The network nodecommunications interface being configured to send a request to the UE tostart transmitting logged measurements in a report message, and toreceive the report message comprising the logged measurements. Thenetwork node processor circuit being configured to determine if thereceived report message comprises an indicator of additional loggedmeasurements not yet transmitted; and if so, to decide if the additionallogged measurements need to be requested.

In a third example of an embodiment, there is disclosed a method in aUser Equipment, UE, for assisting in network based control of reportmessages in a wireless communications network. The UE is being inconnection with a serving network node and configured to transmit reportmessages to the network node upon request. The UE is further configuredto periodically perform radio condition measurements and store theperiodically performed measurements in a UE buffer as loggedmeasurements. The method comprising: receiving a request, in the UE,from the network node to start transmitting logged measurements in areport message; determining if the logged measurements fit in the reportmessage; and if not, including in the report message an indicator ofadditional logged measurements not yet transmitted; and, transmittingthe report message, comprising the indicator, to the network node as aresponse to the request.

In a fourth example of an embodiment, there is disclosed a UserEquipment, UE, for assisting in a network based control of reportmessages in a wireless communications network. The UE is being inconnection with a serving network node and is configured to transmitreport messages to the network node. The UE is further configured toperiodically perform radio condition measurements and store theperiodically performed measurements in a buffer as logged measurements.The UE comprises a UE communications interface and a UE processorcircuit. The UE communications interface is configured to receive arequest from the network node to start transmitting logged measurementsin a report message, and to transmit the report message comprising thelogged measurements. The UE processor circuit is configured to determineif the logged measurements fits in the report message, and if not,indicating in the report message to be transmitted an existents ofadditional logged measurements not yet transmitted.

An advantage achieved by some of the above mentioned embodiments is thatdue to use of indicator in report message of further remaining loggedmeasurements providing the network, i.e. a network node, withinformation needed to decide a timing of transmission of the loggedmeasurements and a timing of when more logged measurements should berequested.

Another advantage achieved by at least some of the above mentionedembodiments is to make it possible to have longer logging durationand/or conduct more frequent measurements without overflow in log memoryin UE e.g. UE buffer.

Another advantage achieved by some of the above mentioned embodiments isto provide the network node with information about logged measurementsmaking it possible to determine the amount of logged measurements keptin a UE.

The foregoing and other objects, features, and advantages will becomeapparent from following more particular descriptions of preferredembodiments and aspects of embodiments as will be illustrated byaccompanying drawings in which reference characters refer to the sameparts throughout various views.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings are not necessarily to scale, emphasis instead being placedupon illustrating principles of the disclosure.

FIG. 1 is a signaling scheme illustrating how logged measurements arereported according to prior art.

FIG. 2 is a schematic block diagram illustrating example embodiments ofa network node and a user equipment.

FIG. 3 is a flowchart depicting an example embodiment of a method in anetwork node.

FIG. 4 is a flowchart depicting further example embodiments of a methodin a network node.

FIG. 5 is a flowchart depicting an example embodiment of a method in auser equipment.

FIG. 6 is a flowchart depicting further example embodiments of a methodin a network node.

DETAILED DESCRIPTION

FIG. 2 illustrates portions of an example embodiment of a communicationssystem/network, and particularly portions of a Radio Access Network(RAN) 20 comprising at least one network node 28 and a wirelessterminal, hereinafter denoted User Equipment, (UE) 30. Depending on aparticular type of RAN utilized and delegation of nodalresponsibilities, the network node 28 may be a base station node e.g.,an NodeB in UMTS or an eNodeB in Long Term Evolution (LTE)) or a RadioNetwork Controller (RNC) node in UMTS. Thus, the UE 30 communicates overradio interface 32 with the network node 28, either directly over radiointerface 32 with the network node 28 in case of the network node 28being a base station type node, or over the radio interface 32 andthrough a base station in the case of the network node 28 being a radionetwork controller (RNC) node or an Mobility Management Entity (MME)which is a control node which processes signaling between the UE and theCore Network (CN) and provides Visitor Location Register (VLR)functionality for the Evolved Packet System (EPS).

As mentioned above, the UE 30 can be a mobile station such as a mobiletelephone (“cellular” telephone) or laptop with wireless capability(e.g., mobile termination), and thus can be, for example, a portable,pocket, hand-held, computer-included, or car-mounted mobile device whichcommunicates voice and/or data via radio access network.

In accordance with one of its aspect, the technology disclosed concernsgeneration and/or transmission and/or use of multiple partial reportmessages with logged measurements such as MDT log packets, also denotedMDT log or MDT log data. As such, FIG. 2 shows an example embodiment ofnetwork node 28 or UE 30, which comprises a UE communication interface42 and a UE processor circuit 40. Note that the UE may be seen as aserving point. The UE processor circuit may include a buffer 44, i.e. UEbuffer, for storing logged measurements, not shown in figure, and inanother embodiment the buffer 44 is within the UE 30.

FIG. 2 also illustrates network node 28 as comprising a network nodeprocessor circuit 50 and network node communications interface 52 (i.e.a communications interface of the network node). The network nodeprocessor circuit 50 may be, or comprise, a logged measurementsrequestor/processor (not shown in figure) to be used for requestinglogged measurements, such as MDT log, in report message(s).

According to one example of an embodiment, the network node 28 is usedfor network based control of report messages comprising loggedmeasurements in a wireless communications network, the network node 28being configured to serve the UE 30, UE, and to receive report messagesfrom the UE 30.

Continuing with the description of FIG. 2, the network nodecommunications interface 52 is, or may be, configured to send request(s)to the UE 30 to start transmitting logged measurements) in reportmessage(s), and to receive the report message(s) comprising the loggedmeasurements. The logged measurements may comprise one or more of thefollowing: measurement time stamps for each performed measurement; UEbuffer state condition; positioning information of UE; periodicallymeasured downlink pilot signal strength; serving cell conditions;transmit power headroom conditions; paging channel failure(s); maximumrequired memory supported by UE; and broadcast channel failure(s).

According to one embodiment, the network node communications interface52 may be configured to receive, from the UE 30, an indication ofexistents of logged measurements that are available. Note, that the“additional logged measurements” indicator is conveyed in the UEinformation report message while the indication of logged measurementsavailable is conveyed in already existing/specified signaling.

According to one embodiment, the network node communications interface52 may be configured to request the report message(s) directly from theUE 30 or from another network node, e.g. RNC, MME, RBS or other similarnode.

According to one embodiment, the network node communications interface52 may be configured to request the report message upon receiving a UEaccess request initiated by a UE handover procedure from another networknode to the network node. The request may for example be a RRCconnection request. The network node communications interface 52 mayalso be configured to receive a network node message from the othernetwork node i.e. another eNodeB, RNC or RBS, comprising UE specificinformation. The UE specific information may further comprise theindicator indicating additional logged measurements not yet transmitted.

The network node processor circuit 50, mentioned above in relation toFIG. 2, is configured to determine if the received report message(s)comprises an indicator of additional logged measurement(s) not yettransmitted; and if so, to decide if the additional logged measurementsneed to be requested. According to one embodiment, the network nodeprocessor circuit 50 may be configured to decide if the additionallogged measurements need to be requested based on one or more of thefollowing: interference level experienced in a cell; radio conditionmeasurements experienced in a cell; available radio resource; networknode capacity; UE buffer state condition etc.

According to one embodiment, the network node processor circuit 50 maybe configured to determine if the indicator indicates that there arelogged measurements in a UE buffer 44 that do, or do not, fit in asingle subsequent report message.

According to one embodiment, the network node processor circuit 50 maybe configured to decide to request all the logged measurements in thebuffer 44 of the UE in one subsequent request, or repeatedly uponreceiving each report message. The decision may also be based onreceived status information of the buffer 44 in the UE 30 being forexample overloaded. Note that configured to or adapted to in relation tofunctionality of circuits and devices mentioned above and throughout thewhole disclosure are expressions that may be used having a similar orsame meaning.

It should be appreciated that the network node processor circuit 50 maycomprise an MDT log requestor/processor 50′ (not shown in FIG. 2) whichmay be implemented in platform fashion, e.g., implemented by acomputer/processor executing instructions of non-transient signalsand/or by a circuit.

Likewise from a UE perspective, reference made to FIG. 2, the UE 30 maybe, or is, used for assisting in network based control of reportmessages comprising logged measurements in a wireless communicationsnetwork. The UE 30 is being in connection with the serving network node28 and is configured to transmit report message(s) to the network node30. The UE 30 may further be configured to periodically perform radiocondition measurements and store the periodically performed measurementsin the buffer 44 as logged measurements. Such logged measurements may beMDT log reports.

The UE communications interface 42 mentioned above in relation to FIG.2, is configured to receive a request from the network node 28 to starttransmitting logged measurements in report message(s), and totransmit/send the report message(s) comprising the logged measurements.The UE processor circuit 40 is configured to determine if the loggedmeasurements fits in the report message(s), and if not, indicating inthe report message to be transmitted an existents of additional loggedmeasurements not yet transmitted.

According to one embodiment of an example implementation of a UE 30 inwhich the UE processor circuit 40 may be, or may comprise, a multiplepartial MDT log reporter 40′ (FIG. 2 dashed lines). The multiple partialMDT log reporter 40′ may comprise a tog report generator and datalogging unit (not shown in FIG. 2). The multiple partial MDT logreporter 40′ works in conjunction with a measurement unit (not shown inFIG. 2), and stores records of measurements in data logging unit. Thelog report generator may further comprise a packet identifier generatorand “more data” i.e. additional data, flag generator.

The technology disclosed above, and in relation to some of the earliermentioned embodiments, includes support for logged measurements, or anMDT log size, which exceeds a maximum size of the report message whichmay for example be a Packet Data Convergence Protocol (PDCP) packet. Thetechnology disclosed herein also introduces and provides an indicationfrom the UE 30 of additional logged measurements or MDT log data thatremains in the UE buffer 44. In accordance with some exampleembodiments, a UE 30 that has stored logged measurements, sometimesdenoted logged data, that are bigger than a single report message i.e.transmission packet, segments the logged measurements, and sends only aportion of the logged measurements that fits into a single reportmessage. The UE 30 also indicates that more logged measurements exist atthe UE 30 in the buffer 44. This indication of further remaining loggedmeasurements allows the network node 28 to decide a timing oftransmission of the logged measurements and a timing of when more loggedmeasurements should be requested. This may for example depend on radiocondition measurements or UE buffer status information.

The UE 30 will take a part of the logged measurements and put into thepayload of the report message. The UE 30 will, if more loggedmeasurements are still available, set a “more” or “additional” bitindicating to the network node 28, or by other means indicate to thenetwork node 28, that there are more logged measurements available inthe UE 30. The network node 28 will then, when it believes more datashould be obtained e.g. based on: interference level experienced in acell; radio condition measurements experienced in a cell; availableradio resource; network node capacity; UE buffer state condition etc.,request more logged measurements. When a request is done then theprocess may be repeated. A new decision may be taken after a new reportmessage is received, and so on. In other words, upon reception ofindication from UE, the network node 28 takes a decision (based oncurrent radio conditions, node capacity) whether the network node 28shall request more logged measurements “data” from the UE now or requestit at a later point in time. This “later point in time” could bepredefined e.g. 15 s later. In one example an internal algorithm may forinstance check to see if no Hand Over (HO) is imminent or other morevital procedure is at hand. The report messages may be lost ifunsuccessfully reporting happens just before a HO. In one example, thenetwork node 28 may be configured to continue requesting reporting oflogged measurements (MDT logs) in report messages until there are nomore logged measurements to report.

An example of an embodiment of a method that may be implemented in thenetwork node 28 is illustrated by FIG. 3. The method is used for networkbased control of report messages comprising logged measurements in awireless communications network. According to the method, the networknode 28 which is being configured to serve a UE 30, receives reportmessages from the UE 30 as mentioned above in relation to FIG. 2. Moreparticularly, the method comprises: sending S62 a request to the UE tostart transmitting logged measurements in a report message; receivingS64 the report message comprising the logged measurements; determiningS66 if the received report message comprises an indicator of additionallogged measurements not yet transmitted; and if so, deciding S68 if theadditional logged measurements need to be requested.

Yet an example of an embodiment of a method for implementation in thenetwork node 28 is illustrated by FIG. 4. The general steps i.e. S72,S74, S76 and S78 correspond to S62-S68 mentioned above. In this examplemethod comprises the network node 28 first receiving S71, e.g. from theUE 30, an indication of existents of logged measurements that areavailable i.e. the UE buffer 44 is not empty or more data exists in UEbuffer 44. Note that this indication is different from the indicatorindicating additional logged measurements.

According to the method, the network node 28 decides to send S72 requestto the UE 30 to start reporting and receives S74 a report message as aresponse. The network node 28 then determines if the report message,which also comprises logged measurements and reporting time stamp,comprises an indicator of additional logged measurements not yetreported. If so, the network node 28 may decide S78 to request theseadditional logged measurements and therefore restarts at S72. If noindicator is included, the network node 28 will await S77 a newindication S71, and restarts the procedure at S72. The network node 28upon deciding S78 to request additional logged measurements may decideto request S79 all logged measurements in one decision instead ofrequesting one subsequent report message at a time. In some exampleembodiments, if the UE 30 indicates that more than one reporting messageis needed for the logged measurements in its UE buffer 44, several bitsmay then be used to indicate that. The network node 28 may then chooseto request multiple messages if the network node 28 so wants.

From a UE perspective, and an example of an embodiment which illustratesa method in a UE, reference is now made to FIG. 5. The UE 30 isconfigured to periodically perform radio condition measurements andstore the periodically performed measurements in a UE buffer 44 aslogged measurements. The method in the UE 30 for assisting in networkbased control of report messages comprising logged measurements in awireless communications network, comprises: receiving S82 a request fromthe network node 28 to start transmitting logged measurements in areport message; determining S84 if the logged measurements fit in thereport message; and if not, including S86 in the report message anindicator of additional logged measurements not yet transmitted; and,transmitting S88 the report message, comprising the indicator, to thenetwork node 28 as a response to the request (S62; S72).

In an example of an embodiment and UE mode, the technology disclosedherein encompasses the following acts and capabilities, as illustratedby FIG. 6:

S90: UE periodically performs measurements and logs radio conditionmeasurements, and possibly detailed positioning information of the UE30, and stores the measurements as logged measurements in the UE buffer44 i.e. in internal memory of the UE 30.

According to one embodiment the logged measurements in UE buffer 44 maybe built up as “records” that include a “time stamp” indicating the timewhen the radio measurement was taken i.e. “measurement time stamp” andlogged measurements. The record may optionally also include detailedposition information of the UEs geographical position. The “records” mayhave variable size. The size of the logged measurements, sometimesdenoted log size, in UE buffer 44 may be bigger than is possible to fitinto one single report message to be sent from UE to network node.

S92: When the UE 30 receives a request from the network node 28 to starttransmitting/reporting logged measurements, the UE 28 takes the numberof “records” i.e. logged measurements, from the UE buffer 44 i.e.internal log, typically in the order of storage, that fits into thereport message, and “advances” an internal pointer such that next-stored“records” will be included in the next report message next time the UE30 is requested to report logged measurements.

This step, i.e. S92, may be preceded by that the UE 30 sending S91 anindication to the network node 28 making it aware of logged measurementsthat are available at the UE 28.

S94: Upon receiving (S92) a request to start transmitting the UE 30 thendetermines if the logged measurements fit in a single report message ornot.

If the logged measurements fit in one report message then no indicatoris added or a dedicated bit for the indicator is left empty i.e. null issent in that bit. Alternatively, an indication is added giving that nomore information is available.

S96: In case the UE 30 has more logged measurements (“records”) storedin the UE buffer 44 not yet reported an indicator of “additional loggedmeasurements” i.e. more data exist is included in the report message.

A “Time stamp” value i.e. “Reporting time stamp” or other identifier isadded to the report message at report message transmission.Alternatively, instead of including a reporting time stamp into thereport message, a sequence number, stepped by one with each reportmessage transmission may be used. Note that this reporting time stamp isdifferent from the measurement time stamp added upon performing andlogging the measurement.

S98: The UE 30 then transmits the report message, including oldestlogged measurements obtained from UE buffer 44, to the network node 28as a response to the request. The report message may therefore compriselogged measurements, a reporting time stamp and detailed positioninginformation of the UE 30.

S99: The UE 30 then deletes the transmitted/reported logged measurementsfrom its buffer, i.e. UE buffer 44, and “advances” an internal pointersuch that next-stored “records” will be included in the next reportmessage. After receiving a new request from the network node 28 the UE30 may then transmit/report logged measurements i.e. repeat stepsS92-S99 and include new logged measurements i.e. “records”, from the UEbuffer 44, according to its internal pointer. Alternatively, or incombination with the reporting, the UE 30 may start again at step S90.

Note, that in current “MDT” general implementation the logging ofmeasurements as logged measurements may only be done when UE is in“idle” state and the sending of logged measurements (MDT logs) in reportmessages may only be done when the UE is in “connected” state.

In some example embodiments, if the UE buffer 44 is almost full or if asize limitation is to be reached, the UE 30 may indicate such conditionsto the network node 28 during the sending S91 or adding that informationduring S96 and sending it during S98. The network node 28 may thenprioritize the retrieval of logged measurements in order not to stoplogging and/or loose logged measurements.

During the repeated sequence of messages between the UE 30 and thenetwork node 28, to convey complete logged measurements from the UE 30to the network node 28, there may be a need to change cell and/orserving Base Station (BS) e.g. during a handover form a first BS (eNB1;NB1; RNC1; RBS1) to a second BS (eNB1; NB1; RNC1; RBS1).

One way to handle cell change and/or BS change situations is that the UEindicate availability when it is connects to the second BS, e.g.according to S91 of FIG. 6. Thus the UE 30 being served by a first BS(e.g. eNB1) and which has for example sent two report messages to firstBS, when performing a handover starts by sending an indication, i.e.sends S91 indication of logged measurements available, to second BS(e.g. eNB2) and then upon request starts reporting to second BS a thirdreport message. Logged measurements that are sent in first and secondreport messages are generally deleted from UE buffer 44 and thereforenot longer available.

A second way, or alternative, to handle this situation is that theinformation that the first BS (e.g. eNB1) has received with respect to“logged measurements available” as of step S91, is transferred to secondBS (e.g. eNB2). The information is transferred based on a request fromsecond BS or automatically, including any related information like tracereferences, etc. The idea here is to include the “indication” in alreadyexisting/specified handover preparation signaling (between eNB1 andeNB2) that is “preparing” the eNB2, before the UE is actually handedover (commanded) from eNB1 to eNB2.

In some situations, “trace references” and “logged measurementsavailable” indication (S91) may be forwarded between RAN 20 nodes. Insuch cases, the UE 30 may also include the trace references in thereport message when the UE 30 transmits a first report message to a RANnode after handover. Note that this first report message, as of theexample mentioned above in relation to the first way of handling thesituation, would be the third report message.

Thus, the technology disclosed herein, in one of its aspects, supportsand/or facilitates a log size exceeding a maximum size of a reportingmessage e.g. a PDCP packet. If the reporting loss/performance isconsidered an issue and needs to be addressed, while a restriction of aUEs total log size, in UE buffer or UE memory, is not wanted, then theUE that has stored logged measurements i.e. logged data, that is biggerthan a single payload PDU (e.g due to PDCP restriction) may segment thelogged measurements and send only a part that fits into a single reportmessage/packet e.g., a message size in the UE response message has afixed size while the MDT log itself has another limit e.g. UE buffersize restriction in UE 30 etc. To handle this, an indication in thereport message e.g. the UE MDT log report, on that additional/morelogged measurements exists is provided. This allows the network node 28to decide the timing for when measurements should be requested and/or(re-)configured. Relying on the “report available bit” only wouldrequire that the UE again transients to RRC connected which may delaythe transfer of logged measurements further, possibly involving UE logmemory being exhausted, new logged MDT configuration or Hand Over (HO)to other Radio Access Technology (RAT) etc.

Thus, with a report message size restriction, the UE 30 shall be able topartition the logged measurements into a maximum fixed size reportingmessage e.g. an RRC message.

Currently the RRC message for MDT also carries information for RACHoptimization (SON) and other optionally configured information. Oneconsequence of the presence of other information in the RRC message/PDUusing a size restriction would be that it possibly depends on the RRCmessage construction and configuration, or that the maximum size of areport message is always set according to a worst case scenario.

In view of the reasons above, no special handling of the RRC message/logsize might be needed as a result of MDT. Retaining normal handling ofRRC messages etc simplifies the considerations that need to taken in thenetwork node 28 and UE 30.

The technology disclosed herein affords several advantages. Among theadvantages are the following. The technology allows for long logging runtimes that may create large logged measurements sizes while the networknode 28 controls the reporting time. The technology facilitates that thenetwork node 28 may determine an appropriate time of reporting withoutloosing logged measurements.

In the above description, for purposes of explanation and notlimitation, specific details are set forth such as particulararchitectures, interfaces, techniques, etc. in order to provide athorough understanding. However, it will be apparent to those skilled inthe art that the above mentioned embodiments may be practiced in a waysthat depart from these specific details. That is, those skilled in theart will be able to devise various arrangements which, although notexplicitly described or shown herein, embody the principles of theembodiments and are included within their spirit and scope. In someinstances, detailed descriptions of well-known devices, circuits, andmethods are omitted so as not to obscure the description of the presentembodiments with unnecessary detail. All statements herein recitingprinciples, aspects, and embodiments, as well as specific examplesthereof, are intended to encompass both structural and functionalequivalents thereof. Additionally, it is intended that such equivalentsinclude both currently known equivalents as well as equivalentsdeveloped in the future, i.e., any elements developed that perform thesame function, regardless of structure.

Thus, for example, it will be appreciated by those skilled in the artthat block diagrams of FIG. 2 herein may represent conceptual views ofillustrative circuitry or other functional units embodying theprinciples of the technology. Similarly, it will be appreciated that anyflow charts as of FIG. 3-FIG. 6, state transition diagrams, pseudo code,and the like represent various processes which may be substantiallyrepresented in computer readable medium and so executed by a computer orprocessor, whether or not such computer or processor is explicitlyshown.

Functions of various elements including functional blocks of FIG. 2,including but not limited to those labeled or described as “computer”,“processor” or “controller”, may be provided through the use of hardwaresuch as circuit hardware and/or hardware capable of executing softwarein the form of coded instructions stored on computer readable medium.Thus, such functions and illustrated functional blocks are to beunderstood as being either hardware-implemented and/orcomputer-implemented, and thus machine-implemented.

In terms of hardware implementation, the functional blocks of networknode 28 or UE 30 may include or encompass, without limitation, DigitalSignal Processor (DSP) hardware, reduced instruction set processor,hardware (e.g., digital or analog) circuitry including but not limitedto Application Specific Integrated Circuit(s) [ASIC], and (whereappropriate) state machines capable of performing such functions.

In terms of computer implementation, a computer is generally understoodto comprise one or more processors or one or more controllers, and theterms computer and processor and controller may be employedinterchangeably herein. When provided by a computer or processor orcontroller, the functions may be provided by a single dedicated computeror processor or controller, by a single shared computer or processor orcontroller, or by a plurality of individual computers or processors orcontrollers, some of which may be shared or distributed. Moreover, useof the term “processor” or “controller” shall also be construed to referto other hardware capable of performing such functions and/or executingsoftware, such as the example hardware recited above.

In the example of FIG. 5 the platform depicted by line 70 has beenillustrated as computer-implemented or computer-based platform. Anotherexample platform for wireless terminal 70(5) can be that of a hardwarecircuit, e.g., an application specific integrated circuit (ASIC) whereincircuit elements are structured and operated to perform the various actsdescribed herein.

Although the description above contains many specificities, these shouldnot be construed as limiting the scope of the invention but as merelyproviding illustrations of some of the presently preferred embodimentsof this invention. It will be appreciated that the scope of the presentinvention fully encompasses other embodiments which may become obviousto those skilled in the art, and that the scope of the present inventionis accordingly not to be limited. Reference to an element in thesingular is not intended to mean “one and only one” unless explicitly sostated, but rather “one or more.” All structural and functionalequivalents to the elements of the above-described embodiments that areknown to those of ordinary skill in the art are expressly incorporatedherein by reference and are intended to be encompassed hereby. Moreover,it is not necessary for a device or method to address each and everyproblem sought to be solved by the present invention, for it to beencompassed hereby.

The invention claimed is:
 1. A method in a user equipment (UE),comprising: transmitting a first indication to a network node that aplurality of logged minimization of drive-tests (MDT) measurements areavailable; receiving a request from the network node to send the loggedMDT measurements; transmitting a logged MDT report to the network node,the logged MDT report comprising a segment of the logged MDTmeasurements; and transmitting a second indication to the network node,the second indication informing the network node that the UE hasadditional logged MDT measurements.
 2. The method of claim 1, whereinthe segment of the logged MDT measurements includes the secondindication.
 3. The method of claim 1, further comprising: collecting MDTmeasurements; and logging the MDT measurements in a memory buffer of theUE.
 4. The method of claim 1, wherein the first indication istransmitted to the network node in a radio resource control (RRC)message.
 5. The method of claim 1, wherein the segment of the logged MDTmeasurement is transmitted to the network node in a RRC message.
 6. Themethod of claim 1, wherein the second indication is transmitted in a RRCmessage.
 7. The method of claim 1, wherein the plurality of logged MDTmeasurements are transmitted to the network node using two or morelogged MDT reports.
 8. The method of claim 7, wherein the two or morelogged MDT reports are transmitted in multiple RRC messages.
 9. A methodin a network node, comprising: receiving a first indication from a userequipment (UE) that a plurality of logged minimization of drive-tests(MDT) measurements are available; transmitting a request to the UE tosend the logged MDT measurements; receiving a logged MDT report from theUE, the logged MDT report comprising a segment of the logged MDTmeasurements; and receiving a second indication from the UE, the secondindication informing the network node that the UE has additional loggedMDT measurements.
 10. The method of claim 9, wherein the segment of thelogged MDT measurements includes the second indication.
 11. The methodof claim 9, wherein the first indication is received from the UE in aradio resource control (RRC) message.
 12. The method of claim 9, whereinthe segment of the logged MDT measurement is received from the UE in aRRC message.
 13. The method of claim 9, wherein the second indication isreceived from the UE in a RRC message.
 14. The method of claim 9,wherein the plurality of logged MDT measurements are received from theUE using two or more logged MDT reports.
 15. The method of claim 14,wherein the two or more logged MDT reports are received from the UE inmultiple RRC messages.
 16. A user equipment (UE), comprising: aninterface configured to: transmit a first indication to a network nodethat a plurality of logged minimization of drive-tests (MDT)measurements are available; receive a request from the network node tosend the logged MDT measurements; transmit a logged MDT report to thenetwork node, the logged MDT report comprising a segment of the loggedMDT measurements; and transmit a second indication to the network node,the second indication informing the network node that the UE hasadditional logged MDT measurements.
 17. The UE of claim 16, wherein thesegment of the logged MDT measurements includes the second indication.18. The UE of claim 16, wherein the interface is further configured tocollect MDT measurements and the UE further comprises processingcircuitry operably coupled to the interface, the processing circuitryoperable to log the MDT measurements in a memory buffer of the UE. 19.The UE of claim 16, wherein the first indication is transmitted to thenetwork node in a radio resource control (RRC) message.
 20. The UE ofclaim 16, wherein the interface transmits the segment of the logged MDTmeasurement to the network node in a RRC message.
 21. The UE of claim16, wherein the interface transmits the second indication to the networknode in a RRC message.
 22. The UE of claim 16, wherein the interfacetransmits the plurality of logged MDT measurements to the network nodeusing two or more logged MDT reports.
 23. The UE of claim 22, whereinthe interface transmits the two or more logged MDT reports in multipleRRC messages.
 24. A network node, comprising: an interface configuredto: receive a first indication from a user equipment (UE) that aplurality of logged minimization of drive-tests (MDT) measurements areavailable; transmit a request to the UE to send the logged MDTmeasurements; receive a logged MDT report from the UE, the logged MDTreport comprising a segment of the logged MDT measurements; and receivea second indication from the UE, the second indication informing thenetwork node that the UE has additional logged MDT measurements.
 25. Thenetwork node of claim 24, wherein the segment of the logged MDTmeasurements includes the second indication.
 26. The network node ofclaim 24, wherein the interface receives the first indication from theUE in a radio resource control (RRC) message.
 27. The network node ofclaim 24, wherein the interface receives the segment of the logged MDTmeasurement from the UE in a RRC message.
 28. The network node of claim24, wherein the interface receives the second indication from the UE ina RRC message.
 29. The network node of claim 24, wherein the interfacereceives the plurality of logged MDT measurements from the UE using twoor more logged MDT reports.
 30. The network node of claim 29, whereinthe interface receives the two or more logged MDT reports from the UE inmultiple RRC messages.